/**
 * Copyright (c) 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule convertFromDraftStateToRaw
 * @format
 * @flow
 */

'use strict';

import type { BlockNodeRecord } from './BlockNodeRecord';
import type ContentState from './ContentState';
import type { RawDraftContentBlock } from './RawDraftContentBlock';
import type { RawDraftContentState } from './RawDraftContentState';

const ContentBlock = require('./ContentBlock');
const ContentBlockNode = require('./ContentBlockNode');
const DraftStringKey = require('./DraftStringKey');

const encodeEntityRanges = require('./encodeEntityRanges');
const encodeInlineStyleRanges = require('./encodeInlineStyleRanges');
const invariant = require('fbjs/lib/invariant');

const createRawBlock = (block: BlockNodeRecord, entityStorageMap: *) => {
  return {
    key: block.getKey(),
    text: block.getText(),
    type: block.getType(),
    depth: block.getDepth(),
    inlineStyleRanges: encodeInlineStyleRanges(block),
    entityRanges: encodeEntityRanges(block, entityStorageMap),
    data: block.getData().toObject()
  };
};

const insertRawBlock = (block: BlockNodeRecord, entityMap: *, rawBlocks: Array<RawDraftContentBlock>, blockCacheRef: *) => {
  if (block instanceof ContentBlock) {
    rawBlocks.push(createRawBlock(block, entityMap));
    return;
  }

  invariant(block instanceof ContentBlockNode, 'block is not a BlockNode');

  const parentKey = block.getParentKey();
  const rawBlock = blockCacheRef[block.getKey()] = {
    ...createRawBlock(block, entityMap),
    children: []
  };

  if (parentKey) {
    blockCacheRef[parentKey].children.push(rawBlock);
    return;
  }

  rawBlocks.push(rawBlock);
};

const encodeRawBlocks = (contentState: ContentState, rawState: RawDraftContentState): RawDraftContentState => {
  const { entityMap } = rawState;

  const rawBlocks = [];

  const blockCacheRef = {};
  const entityCacheRef = {};
  let entityStorageKey = 0;

  contentState.getBlockMap().forEach(block => {
    block.findEntityRanges(character => character.getEntity() !== null, start => {
      const entityKey = block.getEntityAt(start);
      // Stringify to maintain order of otherwise numeric keys.
      const stringifiedEntityKey = DraftStringKey.stringify(entityKey);
      // This makes this function resilient to two entities
      // erroneously having the same key
      if (entityCacheRef[stringifiedEntityKey]) {
        return;
      }
      entityCacheRef[stringifiedEntityKey] = entityKey;
      // we need the `any` casting here since this is a temporary state
      // where we will later on flip the entity map and populate it with
      // real entity, at this stage we just need to map back the entity
      // key used by the BlockNode
      entityMap[stringifiedEntityKey] = (`${entityStorageKey}`: any);
      entityStorageKey++;
    });

    insertRawBlock(block, entityMap, rawBlocks, blockCacheRef);
  });

  return {
    blocks: rawBlocks,
    entityMap
  };
};

// Flip storage map so that our storage keys map to global
// DraftEntity keys.
const encodeRawEntityMap = (contentState: ContentState, rawState: RawDraftContentState): RawDraftContentState => {
  const { blocks, entityMap } = rawState;

  const rawEntityMap = {};

  Object.keys(entityMap).forEach((key, index) => {
    const entity = contentState.getEntity(DraftStringKey.unstringify(key));
    rawEntityMap[index] = {
      type: entity.getType(),
      mutability: entity.getMutability(),
      data: entity.getData()
    };
  });

  return {
    blocks,
    entityMap: rawEntityMap
  };
};

const convertFromDraftStateToRaw = (contentState: ContentState): RawDraftContentState => {
  let rawDraftContentState = {
    entityMap: {},
    blocks: []
  };

  // add blocks
  rawDraftContentState = encodeRawBlocks(contentState, rawDraftContentState);

  // add entities
  rawDraftContentState = encodeRawEntityMap(contentState, rawDraftContentState);

  return rawDraftContentState;
};

module.exports = convertFromDraftStateToRaw;